1. Field of the Invention
The present invention relates to an intake device of a V-type engine of a motorcycle.
2. Related Art
A motorcycle is equipped with a V-type engine having two cylinders including one inclined to the front side and the other inclined to the rear side in the vehicle longitudinal direction.
There is known an arrangement of air/fuel mixture supply device such as a carburetor or a throttle body constituting an intake device and an air cleaner for purifying the intake air as disclosed in the Japanese Patent Laid-Open Publication No. HEI 8-108877. That is, a recess is formed on a lower surface of a fuel tank located above the engine with a center air cleaner being arranged therein, and side air cleaners are arranged on right and left side surfaces of the engine, respectively. Further, an internal space of these side air cleaners is divided into a dirty side and a clean side with an air filter being interposed therebetween. An intake pipe extending right and left from the center air cleaner is connected to the dirty side of the side air cleaner, while the clean side being connected to the mixture supply device.
An external air to be sucked into the engine first enters the center air cleaner and then, after being divided into right and left, it flows into the dirty side of the side air cleaner. After being purified by the air cleaner, the external air flows to the mixture supply device through the clean side and is taken into the engine.
In this way, if three air cleaners in total are provided at the center and side portions, and the air sucked from the center air cleaner is supplied to the mixture supply device after being divided into the right and left side air cleaners, intake passages of the front and rear cylinders can be made substantially independent so that intake interference is difficult to occur, and an intake efficiency can be improved to some extent. In addition, attaching/detaching working for washing or replacement of the air filter inside the side air cleaner is favorably done.
However, since the air filter is located immediately before the mixture supply device in the arrangement mentioned above, the capacity of the clean side cannot be increased and the intake efficiency cannot be largely improved by using an intake inertia effect, for example. If the capacity of the side air cleaner is increased, the intake efficiency can be improved more or less. However, this arrangement makes the side air cleaner extend outward in the vehicle-width direction, thereby degrading compactness. Moreover, the side air cleaners will interfere with the knees of a rider, impairing riding stability.